The electrical gradient, created by the outflow of more positive sodium ions than the inflow of positive potassium ions, is used by neurons and muscles to create the action potentials responsible for nervous system function and muscular contraction. The chemical gradient, which is created by the higher concentration of sodium ions in the extracellular space as opposed to the cytoplasm, results in the tendency of sodium ions to flow down their concentration gradient and back into the cytoplasm through other transmembrane proteins. What is the net effect of the sodium-potassium pump?
Responses
A The sodium-potassium pump uses ATP to maintain a zero charge balance between the internal and external environments of the cell.The sodium-potassium pump uses ATP to maintain a zero charge balance between the internal and external environments of the cell.
B The sodium-potassium pump facilitates the movement of sodium and potassium ions across the membrane in a manner that keeps the concentration gradient at equilibrium.The sodium-potassium pump facilitates the movement of sodium and potassium ions across the membrane in a manner that keeps the concentration gradient at equilibrium.
C The sodium-potassium pump uses ATP to pump three potassium ions out of the cell for every three sodium ions pumped into the cell, thus maintaining neutral conditions.The sodium-potassium pump uses ATP to pump three potassium ions out of the cell for every three sodium ions pumped into the cell, thus maintaining neutral conditions.
D The sodium-potassium pump uses ATP to pump two potassium ions into the cell for every three sodium ions pumped out, against the concentration gradient, creating a membrane potential.The sodium-potassium pump uses ATP to pump two potassium ions into the cell for every three sodium ions pumped out, against the concentration gradient, creating a membrane potential.